Overload circuit breaker



Sept 25, 19340 M. GUETT OVERLOAD CIRCUIT BREAKER Filed Jan. 30, 1932 enema Sept. 25, 1934.

OVERLOAD CHRCIUIIT BREAKER Monroe Guett, Hartford, (Comm, assignor to The Arrow-Hart & ll-llegeman Electric Company, Hartford, Conn, a corporation of Connecticut Application January 30, 1932, Serial No. 589,90?

ll Claims.

This invention relates to devices for opening and closing an electric circuit.

More particucircuit breaker which will be reliable in operation when manually actuated and which will open quickly when operated by an overload or excess current in the circuit.

Another object is to provide a circuit breaker with tripping means independent of the manual actuating means of the dev ice.

Other objects and advantages of my invention will be apparent as it is described in connection with the accompanying drawing.

In the drawing:

Figure 1 is a side elevation view of my invention showing the parts in circuit making position.

Figure 2 is a side elevation view of my invention showing the parts in the position taken when the contacts are moved, by the manual means, to open a circuit.

operating Figure 3 is a side elevation view showing the parts of the device in the position they assume upon operation of the device due to an overload.

Figure 4 is an end elevation the line 44 of Figure 1.

view taken along Figure 5 is an elevation section view taken along the line 55 of Figure 4.

Referring to the drawin gthe device may be mounted upon an insulating base 10 which has a pair of spaced stationary contacts 12, 13,

mounted at one end there of and thermal tripping device 15 mounted at the opposite end thereof. The thermal tripping device may be of any suitable construction such described in my copending 588,214 filed January 22nd,

for example as that application Serial No. 1932 now Patent No.

1,966,444, or the tripping of the circuit breaker may be accomplished by electromagnetic means of any suitable conventional construction.

The stationary contacts 12, 13 are bridged by movement about one or the by either manual or autom as hereinafter more fully other of two pivots, atic operating means, described.

The movable parts of the circuit breaker are carried by a sheet metal frame 20 which is bent into U-shape and has its transverse portion 20?) secured to the base 10 by screws or any other suitable securing means. Between the upstanding parallel side plates 20a of the frame is located the mechanism whereby a circuit breaker may be manually actuated.

The mechanism for manually actuating the device comprises an insulating handle 24 which is secured on one end of an arcuate lever 26. This lever 26 is pivotally mounted at its other or inner end upon the transverse portion 20b of the circuit breaker frame. The pivotal mounting of this lever 26 is accomplished (see Fig. 5) by forming a semicircular recess 27 in the lower side of the inner end of the lever, and providing a pair of neighboring slots 29, 29a in the portion 20b of the frame, the slots being of size convenient for the reception of the end and shank of the lever 26 during oscillation of the lever. The metal between the slots 29, 29a is pressed up into semicylindrical form to afford a good bearing surface for the lever 26. Under the central portion of the handle 24 a hook 28 is formed upon the lever 26. A coil spring 30 has one end engaging with the hook 28 and the other end engaging with the transverse central portion 34a of a pivotally mounted U-shaped switching member 34. The switching member 34 is pivotally mounted between the upstanding side plates 20a of the frame 20 by means of coaxial pins 36 which pass through the ends of the switching member and the plates 20a, in a line parallel to and substantially vertically above the pivotal mounting of the lever 26.

Those skilled in the art will recognize the principle employed and understand the snap action of the switching member upon movement of the spring 30 through the pivotal axis of the switching member. Therefore further explanation of this portion of the device will be unnecessary. It should be noted however, that the movement of the switching member to the left in Figures 1-3 is limited by the transverse portion 34 100 of the switching member coming into engagement with the frame 20. Movement ofv the switching member in the opposite direction is limited by a pin (not visible) on the inside of one arm of the switching member, coming into engagement 105 with the frame 20.

The carrier member 19 for the contact bridging member 17 is U-shaped, having the bridging contact member 17 mounted on the transverse portion 19a thereof but insulated therefrom. The n its ' -From the foregoing and by 55' side arms ofthe carrier 19are parallel and in the form of bell crank levers. The carrier is 'pivotally mounted on the switching member 34 by means of coaxial pivot pins 38 passing through the extremities of the side arms of the carrier, and through the side arms of the switching member in a line parallel to and just above the trans- Y verse portion 34a of the switching member.

A toggle mecli'ani'smis connectedwith the carrier 19' means of coaxial pivot pins 40 which pass through the elbows of the bell crank side arms of the carrier at such a distance from the pins 38 that when the switching member and the outer ends of the side arms of the carrier are lined up i. e. in the same plane, then the pins 40 will'be coaxial with pins 36.

The toggle mechanism comprises a pair of parallel straight links 42 and a pair of angular links 44. One end of each of the straight links 42 is connected by pivot pin 40 withthe carrier 19. The other end of each straight link 42 is pivotally connected with one end of each link 44. The links 44 are-each pivotally mounted at the sides of the frame on an axle 48 passing through the elbows of the links-44 and the frame 20 in an axis spaced from the axis of the. pins 36 but parallel thereto and at approximately the same distance from the base 10 as the axis ofpins 36. The other ends of the links 44, i. e. those which are not connected with the links 42, are joined-by a cross bar 45,-,the cross bar and the links 44 preferably being made'of one-piece of metal stamped and bent into the form described. Springs 50 on each side of the device connect the pivot pins 40 and axle 48, tending to collapse the toggle. A pin '49 in the side of the frame prevents overthrow cf the toggle when the links are straightened out into a dead center position as shown in Figures 1, 2 and 4. A spring 54 is anchored to the lower part of the switch frame and is connected with a lateral extension of the link 44 to carry the toggle into dead center position, as the toggle is straightened out when the deviceQis'being set. In Figures 1 and 2, the toggle mechanism' -is shown in extended position, and in Figure :3- the toggle is shown collapsed. The -.crossbar 45 of the togglelinks 44 is adapted tobe engaged by the thermal tripping mechanism 15 or whatever tripping mechanism isaused and by suchengagement the link 44 is caused to--pivot about the pin 48, thus tending to collapse the toggle and to draw the pin 40 toward the pin 48.- l a,

reference to the drawing, it will be observed that upon movement of the link 44 of the toggle mechanism into hori- 'zontal positiom -the .link 42 is also carried into horizontal position, andthe toggle is straightened out.- The links 44 and 42 are made of such with a snap from left to right carrying carrier 19 with it and causing the upper portion of one of-the side arms of the carrier: 19 to slide along astq'pand guide pin 56in the side of the frame. l it'the end of such movement the parts are in the position of Figure 2. Now if the handle is moved '36 will be accompanied by pivotal movement of into the position of Figure 1, the switching member will be actuated with a snap. Since the pins 40 and 36 are coaxial, pivotal movement of the switching member 34 about the axis of the pins the carrier 19 about the same axis. This manipulation of the handle causes engagement of the switch contacts. The reverse will cause separation of thecontacfii. 1 Automatic operation of the switch upon the occurrence of an excess current in the circuit is accomplished by a tripping member engaging with the cross piece 45 of the toggle links 44 causing said links to pivot about pins 48. This moves the toggle links out of alignment and the actionof the spring 50 thereupon pulls the pivot pin 40 and the carrier 19 connectedthereto toward the pivot pin 48. This action causes the carrier 19 to pivot about pins 38, thus disengaging the movable contacts from the stationary contacts.

Many modifications within the scope of my invention will occurto those skilled in the art, therefore I do not limit myself to the specific em- Y bodiment shown. I v

This invention is an improvement upon the inventions shown in my copending applications Serial No. 500,352 filed December 5, 1930, now Patent No. 1,911,893, and Serial No. 588,214 filed January 22nd, 1932, now Patent No. 1,966,444. I make no claim herein to subject matter common to these inventions, such matter being claimed broadly in said applications.

1. An electric switch comprising fixed and movable contacts, an oscillatable member pivotally mounted about a fixed axis, a manually actuable member having a resilient lost motion connection with said oscillatable member for moving said oscillatable member with a snap after pre determined movement of said manually actuable member, a carrier for said movable contact, a movable pivot for mounting said carrier on said oscillatable member, means normally holding said carrier in position to pivot about the fixed axis of said oscillatable member, said means being releasable on overload to permit said carrier to pivot about said movable pivot.

2. An electric switch comprising fixed and mov able contacts, a carrier for said movable contact, manually operable means to move said carrier with a snap motion to open and to closed circuit positions, automatically operable means to move said carrier on overload, a pivot throughone portion of said carrier about which said'carrier pivots during manual operation of the switch, and another pivot through another portion of said carrier about which said carrier pivots during automatic operation of the switch.

3. An electricswitch comprising fixed and movable contacts, a manually controlled switching member movable with a snap, a carrier for said movable contact, said carrier having a pivotal connection with said switching member and moving with it during manual operation of the switch, 1 and means operable on overload to cause said carrier to pivot about its connection with said switching member, said means including a stationarily mounted current responsive device.

4. An electric switch comprising fixed and movable contacts, a carrier forsaid movable con tact, manually operable meansto move said car: rier with a snap motion to open and to closed circuit positions, toggle mechanism to move said carrier on overload, said toggle mechanismholding said carrier to pivot about another 1,975,041 ing said carrier for movement about one pivot during manual actuation of the switch and causpivot upon automatic operation of the switch.

5. An electricswitch comprising fixed and movcontacts, means for causing engagement and disengagement of said contacts with a snap motion, a carrier for said movable contacts normally pivoting about an axis through one portion of itself,

togglemechanism for positioning said carrier'for pivoting about said axis, means operable on overload to collapse said toggle mechanism and cause said carrier topivot about another axis through another portion of itself.

6. An electric switch comprising fixed and movable contacts, means for causing engagement and disengagement of said contacts with a snap motion, a carrier for said movable contacts, means pivotally connected to said carrier for manually controlling said carrier, means operable on overload and pivotally connected to said carrier to move said carrier, said carrier pivoting about its pivotal connection with the overload operating means during manual operation of the switch and pivoting about its pivotal connection with said manual controlling means upon automatic operation of the switch.

7. An electric switch comprising fixed and movable contacts, a manually controlled switching member, pivoted about a fixed axis, a carrier for said movable contact having a pivotal connection with said switching member, means including a pair of toggle links to operate said switch on overload, said carrier pivoting about the fixed axis of said switching member during manual operation of the switch and pivoting about the axis of its pivotal connection with said switching member upon automatic operation of the switch.

8. An electric switch comprising fixed and movable contacts, manual switch operating means, a switching member pivoted about a fixed axis, a resilient lost motion connection connecting said manual means and said switching member to move said switching member with a snap, a carrier for said movable contact having a' pivotal connection with said switching member, means to operate said switch on overload, said carrier pivoting about the fixed axis of said switching member during manual operation of the'switch and pivoting about the axis of its pivotal connection with said switching member upon automatic operation of the switch.

9. An electric switch comprising fixed and movable contacts, a switching member pivoted about a fixed axis, manually operated snapping mechanism for said switching member, a carrier for said movable contact pivotally' connected with said switching member, toggle mechanism holding said carrier in position to pivot about said fixed axis during manual operation of the switch, means operable on overload to collapse said toggle mechanism causing said carrier to pivot about its connection with said switching member.

10. An electric switch as claimed in claim 8, wherein the means to open the switch on over-100 load includes a pair of toggle links.

11. An electric switch comprising fixed and movable contacts, a carrier for said movable contact, manually operable means to move said carrier including a resilient lost motion connection, 195 said connection moving said carrier with a snap after said manually movable means has been moved a predetermined distance, automatically operable means to move said carrier on overload, 

